This invention relates to the field of air cleaners, and provides an air cleaner which regenerates itself by catalytic combustion.
In a closed space such as the interior of a spacecraft or a submarine, it becomes important to purify the air with minimal expenditure of energy, and with devices that occupy very little space. Furthermore, no make-up air can be brought in from the outside, and all of the cleaned air must be returned to the closed space. U.S. Pat. No. 4,911,894 describes in detail the theory of operation of a spirally-wound catalytic air cleaner. This specification hereby incorporates by reference the disclosure of the above-cited patent. In the above-cited patent, one forms the air cleaner from two strips of metal foil, wound together to form a double spiral. The double spiral defines two flow channels, one leading into the core of the spiral, and the other leading out. A combustion catalyst coats the strips of foil. The incoming air stream receives heat by heat exchange with the outgoing air stream, and also from a heater located in the core of the spiral. Catalytic combustion occurs on the surfaces of the strips.
The present invention provides an alternative arrangement, in which the cleaning of the air occurs entirely at ambient temperature, without expenditure of electrical energy and without combustion. Instead, one expends energy only during a periodic regeneration phase, at which time one uses catalytic combustion to remove impurities absorbed by the cleaner.
For cleaning the air in a passenger airliner, the air cleaner is simpler. The cleaning process is the same as described above, but there is no catalytic combustion and no heat exchange. Instead, the impurities are rejected to the outside of the airliner, and make-up air is brought in from the outside.